This invention relates in general to an elastic supports. More specifically, it relates to an elastic knee support that provides a direct and independently adjustable compressive force on the knee cap.
A wide variety of orthopedic appliances and elastic braces are known. They are used to support an injured knee. They also can be used on healthy knees to support and thereby reduce the likelihood of injury to the knee and surrounding tissue, particularly when the user is engaged in a sports or occupational activity that subjects the knee to unusual stretching or load bearing. However, orthopedic appliances and orthopedic braces are generally not used by the general public for minor sprains or to protect a healthy knee during strenuous activities.
Taping of a knee, whether to promote healing or to protect a knee prophlylactically, is known, but correct taping requires skill and is time consuming. Moreover, it often interferes with normal movement of the knee, chafes, and is painful to remove. Orthopedic appliances, on the other hand, are typically cumbersome devices having articulated metal supports. These devices are heavy, expensive and uncomfortable to wear. They also typically attach to the leg over a substantial portion of the thigh and calf, typically at least twelve inches at both locations. U.S. Pat. No. 4,407,276 to Bledsoe is exemplary of these appliances.
A wide variety of orthopedic brace designs using resilient materials and no articulated metal members have also been proposed. Some are used commercially. One approach has been to use a sleeve or patch formed totally or in part of an elastic material reinforced by, or supporting rigid or somewhat flexible members or cushioning pockets. U.S. Pat. Nos. 3,189,919; 3,677,265; 3,934,583; 3,945,047 and 4,765,318 describe braces of this general type. Another style is to use multiple elastic wrappings and/or long straps wrapped in criss-cross fashion in an attempt to fix the brace reliably on the leg and to develop some compressive force while a greater freedom of movement than with other appliances or braces. U.S Pat. Nos. 3,046,989 and 3,945,046 are braces of this general type. U.S. Pat. No. 4,378,009 discloses a brace formed as an elongated plastic tube which can be wrapped around a body part. The tube can be solid or inflatable. In one form it is formed in a sheet of vinyl having Velcro mounting tabs to hold the assembly in place when it is wrapped around a leg. One frequent disadvantage of braces formed of multiple components is that the edges or seams can pinch the skin or rub it as the knee is flexed. Another disadvantage is that known braces do not provide a direct compressive force on the patella that is adjustable and is independent of the arrangement that secures the brace in a desired position or the leg.
U.S. Pat. No. 4,353,362 to DeMarco discloses an "unfolding type", wrap on brace with oppositely directed tapes and VELCRO, hook and loop fasteners above and below the kneecap. The brace has inbuilt, K-shaped stays on opposite sides of the kneecap to increase the rigidity of the support. The tapes are wrapped multiple times around the thigh and calf and then secured using the fasteners. While DeMarco avoids some of the problem of prior art braces, it does not provide an adjustable compressive force that is applied directly to the kneecap (patella) or a compressive force that is independent of securing of the support on the leg or knee.
Perhaps the most common form of orthopedic knee support (not brace) sold commercially is simply a tubular sleeve of an elastic material that pulls over and grips the knee and adjoining regions. While this device is simple, it must be manufactured in a variety of sizes in order to fit the normal range of adult leg sizes properly. Moreover, even if properly sized these supports can slide up or down the leg during use. They also buckle and chafe the skin during flexure of the knee. U.S. Pat. No. 4,084,584 to Detty discloses a type of elastic sleeve support with a padded opening around the patella and a two piece construction secured by a pair of vertical seams. This support can buckle and chafe. Also, it does not provide an independently adjustable compressive force directly on the patella.
It is also known to manufacture a simple tubular support where one portion of the support, below the knee, is a tube of an elastic material and a portion above the knee is wrapped around the leg and is secured by a VELCRO tab. While the upper wrap introduces some adjustability, this support nevertheless must be sold in a variety of sizes. Also, it provides no direct compressive support for the patella, let alone an adjustable compressive support.
It is therefore a principal object of this invention to provide a lightweight, flexible knee support that provides a direct and adjustable compressive force on the patella and/or immediately surrounding tissue.
A further principal object is to provide a support with the foregoing advantages that is made in a single size, yet fits all wearers within a broad grouping with a tailored fit that is comfortable and securely locates the support on the leg.
Another object of the invention is to provide a support with all of the foregoing advantages which does not irritate the user with seam bite, buckling or rubbing at the back of the knee, even through repeated flexures of the knee through a full range of motion.
A further object is to provide a support with the foregoing advantages which offers little interference with normal movements of the leg at the knee.
A further object is to provide all of the foregoing advantages while at the same time retaining a significant portion of the body heat at the patella that would otherwise be radiated away.
A still further object is to provide all of the foregoing advantages at a competitive cost of manufacture using known materials and fabrication techniques.